天然矿物原料超临界水热法快速合成类沸石材料及其脱汞性能

发布时间：2018-05-22 17:51

  本文选题：超临界水热合成 + 煤矸石　； 参考：《太原理工大学》2015年硕士论文

【摘要】：煤矸石是与煤共生的一种较为坚硬、含有少量碳的黑色岩石，是我国目前堆存量最多的工业固体废物之一。大量的煤矸石占用了耕地，且严重污染了自然环境。目前，煤矸石主要用于制造砖、水泥与其它建筑产品或提取化工产品，但存在利用率均不高及产品附加值低的缺点。煤矸石含有大量的高岭石成分。高岭石是层状硅酸盐粘土矿物，是合成沸石分子筛的理想原料之一。沸石分子筛具有离子交换性能、吸附分离性能及催化性能，在环境保护、石油化工、化学工业等领域有着很广泛的应用。利用煤矸石合成沸石分子筛可充分提高煤矸石利用率，产品的经济附加值也很高。目前矿物原料合成沸石分子筛的主要方法有水热合成法、碱溶法、碱熔-水热法、微波合成法和蒸汽相合成法，但以上合成方法操作过程复杂繁琐，合成时间长。超临界水热法具有许多独特的性能：反应在均相的环境中进行、易于溶入多孔的物质中、化学反应速率高。采用超临界水热法合成类沸石分子筛可简化合成过程、极大地缩短反应时间。本文基于超临水的独特性质，以天然矿物原料高岭石和煤矸石为原料，使用超临界水热法合成类沸石。考察碱溶液类型、碱溶液浓度、超临界反应时间和温度对类沸石合成的影响。采用X射线衍射（XRD）、扫描电子显微镜（SEM）、热重分析（TG-DTG）与傅里叶变换红外光谱（FT-IR）等分析手段，对产物进行测定表征。并通过脱除废水中汞离子的效率来考察合成的类沸石材料的吸附性能。实验结果表明： （1）反应温度为400℃时，高岭石与1mol/L碳酸钠溶液、1mol/L氢氧化钠溶液与2mol/L氢氧化钾溶液在超临界水热条件下，，分别成功合成了方钠石、钙霞石与钾霞石这些类沸石材料，产物结晶度很高，粒径分布较均匀。合成类沸石最佳反应时间都为5min，和传统水热合成法相比，反应时间大幅度缩短。 （2）高岭石合成的三种类沸石材料中，钾霞石的脱汞效率最高，吸附性能最好。同时，合成的三种类沸石材料的吸附性能都要高于原料高岭石。 （3）煤矸石在相同的条件下也成功合成了方钠石、钙霞石与钾霞石这些类沸石产物，煤矸石中炭质等杂质对合成类沸石结晶度影响很小。钾霞石具有很好的热稳定性。 （4）煤矸石合成钾霞石产物对汞离子的吸附效率最高，可达到95.71%。煤矸石合成产物中炭质对汞离子具有一定的吸附性能，这使得煤矸石超临界水热合成的产物比高岭石合成产物的吸附效率高。
[Abstract]:Coal gangue is a kind of hard black rock containing a small amount of carbon, which is one of the industrial solid wastes in our country. A large number of coal gangue occupied cultivated land, and seriously polluted the natural environment. At present, coal gangue is mainly used to make bricks, cement and other building products or to extract chemical products, but the utilization ratio is not high and the added value of products is low. Coal gangue contains a great deal of kaolinite. Kaolinite is a layered silicate clay mineral and one of the ideal raw materials for the synthesis of zeolite molecular sieves. Zeolite molecular sieves have been widely used in many fields such as environmental protection, petrochemical industry, chemical industry and so on. Zeolite synthesized from coal gangue can improve the utilization ratio of coal gangue, and the economic added value of the product is also very high. At present, the main methods of synthesizing zeolites from mineral raw materials include hydrothermal method, alkali solution method, alkali melt hydrothermal method, microwave synthesis method and steam phase synthesis method. The supercritical hydrothermal process has many unique properties: the reaction takes place in a homogeneous environment and is easily dissolved into porous materials, resulting in a high chemical reaction rate. The synthesis of zeolite-like molecular sieves by supercritical hydrothermal method can simplify the synthesis process and greatly shorten the reaction time. In this paper, based on the unique properties of superimminent water, zeolite like zeolite was synthesized by supercritical hydrothermal method with kaolinite and gangue as raw materials. The effects of alkali solution type, alkali solution concentration, supercritical reaction time and temperature on the synthesis of zeolites were investigated. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TG-DTG) and Fourier transform infrared spectroscopy (FTIR). The adsorption properties of the synthesized zeolite-like materials were investigated by removing mercury ions from wastewater. The experimental results show that: When the reaction temperature is 400 鈩

本文编号：1923050